As we all know, marathon is a long time, long-distance strenuous exercise, the distance is basically tens of kilometers. When people exercise vigorously for a long time, the oxygen consumption of the heart will increase, and the heart muscle will suffer from different degrees of strain. Of course, healthy people will not appear in this situation, but with the growth of age, some people can appear atherosclerosis or cardiovascular stenosis, this situation may aggravate the myocardial oxygen consumption. In the process of long-distance running, the heart is overloaded, i.e., the myocardial oxygen consumption is too high, and cardiovascular spasm occurs, and this condition can lead to sudden death, i.e., sudden cardiac arrest. When a marathon runner is found to fall to the ground, the first thing to determine is also whether it is sudden death, because some people are in a coma state, which is not related to sudden death. Sudden death first of all the patient will have loss of consciousness and the patient should be called. If the patient is not called, it means that the patient has lost consciousness, and then listen to the heartbeat. If no heartbeat can be heard, it means that the patient’s heart has stopped beating, which can be judged as sudden death, and cardiopulmonary resuscitation needs to be performed immediately.